1. Technical Field
The present invention relates to a discharge lamp, a light source device, and a projector.
2. Related Art
In the past, there has been used a high-pressure discharge lamp as a discharge lamp for a projector (see, e.g., Japanese Patent No. 4,400,095).
Incidentally, in the discharge lamp described above, the metal constituting the electrode evaporates, and then circulates in the light emitting tube due to the convection flow caused by the arc discharge. When the convection flow collides with a base part of the electrode such as a coil part, the metal circulating in the light emitting tube due to the convection flow is deposited on the base part of the electrode. Therefore, the metal is sequentially deposited on the same place of the base part of the electrode, and thus, a projection of the metal is formed in the base part of the electrode in some cases.
If the projection of the metal is formed in the base part of the electrode, there is a possibility that the discharge occurs between a tip of the projection and the inside wall of the light emitting tube to deteriorate the inside wall of the light emitting tube. Thus, it becomes easy for the material circulating in the light emitting tube to be deposited on the deteriorated part of the inside wall of the light emitting tube, and there is a problem that blackening and devitrification occur.